FrequencyModulation

FrequencyModulation[fc, {fm, pd}, dur]creates a Sound object that is a frequency-modulated sinusoid, having carrier and modulating frequencies fc and fm, measured in hertz, peak deviation pd hertz, and a duration of dur seconds.

Cascade frequency modulation is a type of frequency modulation where the modulating frequency is itself modulated, thus cascading the modulation.

In contrast to cascade frequency modulation, Parallel frequency modulation is a technique where the carrier frequency is modulated by two or more modulating frequencies that do not modulate each other.